jstarr@ANAD.ARPA (James Starr Network Control Branch USAISC Anniston) (08/05/87)
Lightning is a very funny annimal. Even those who devote their entire life to studing the phenomenon do not know it all and spend time arguing amongst themselves. Some facts are known. Lightning does most of its damage to sensitive electronic devices without even a direct hit on power or phone lines. Among other things, lightning creates a very strong magnetic field with every stroke. This is the static you hear on your AM radio even tho the storm is many miles away. If there is a lightning bolt very near you, even cloud to cloud, the magnetic field created can induce damaging voltages into modems, CRTs, radios and other such devices even tho they are unpluged from the power and phone lines. There is little or nothing that can be done to prevent this type of damage except to shield your gear in a well grounded metal box. Have you ever been outside when a thunder cloud was passing overhead and felt your skin tingle and have the hair on your arm stand up?? That effect can and will cause currents to be generated in electronic devices and will cause damage if the current is strong enough. I unplug my phone cord from the modem, not from the wall, and unplug the CRT power cord from the CRT, not the wall outlet. That leaves less wire hanging for stray voltages to be be induced in.. Good Luck.. Jim Starr